1. Nasal Cavity, Paranasal Sinuses, Pterygopalatine Fossa
Mikel H. Snow, Ph.D.
Dept. of Cell & Neurobiology
Neuroscience System
July 25, 2018

2. Nasal Cavity and Paranasal Sinuses
Lecture part 1
Nasal Cavity and Paranasal Sinuses

3. Objectives for Nasal Cavity & Paranasal Sinuses:
Sinusitis affects 10% - 30% of Americans each year, and the annual cost for treatment is greater than $11 billion.
Objectives for Nasal Cavity & Paranasal Sinuses:
Functions of the paranasal sinuses
Locations, relationships & drainages of the nasal sinuses
Anatomical rationale underlying sinusitis symptoms

4. There are 4 pairs of paranasal sinuses, each named according to the bone they lie in:
Frontal
Sphenoid
Ethmoid
Maxillary
Mucosa lining sinuses produces nitric oxide which is antiviral and bacteriostatic. Thus, they assist the immune system.

5. Turbinates are delicate, scroll-like bones that project medially into the nasal cavity to increase surface area. They are covered by a thick mucous membrane.
Head CT - Coronal
Turbinates

6. A meatus is the space immediately lateral to the turbinate.
The scroll-like turbinates that project from the lateral nasal wall have slit-like spaces (meatuses) lateral to each turbinate.
Superior turbinate
Middle turbinate
Inferior turbinate
Vestibule
A meatus is the space immediately lateral to the turbinate.

7. Sphenoethmoidal recess:
The four pairs of paranasal sinuses, plus the nasolacrimal duct, drain into the nasal cavity.
Superior meatus:
Ethmoids (post.)
Sphenoethmoidal recess:
Sphenoid sinus
Middle meatus:
Frontal sinus
Maxillary sinus
Semilunar hiatus
Ethmoids (ant & mid)
Inferior meatus:
Nasolacrimal duct

8. Nasal Cavity CT ? Uncinate process 2 septum Middle 1 Maxillary sinus
Middle turbinate
Inferior turbinate

9. Right Maxillary Sinus Surgery

10. Objectives for Pterygopalatine Fossa:
Location of pterygopalatine fossa within the skull.
Bony openings/structures connecting to pterygopalatine fossa
Parasympathetic pathways for innervating the:
lacrimal gland
nasal mucous glands
palatine mucous glands
Somatosensory innervation to nasal cavity & palates.

11. Pterygomaxillary fissure
The pterygopalatine fossa is a small space located just medial to the pterygomaxillary fissure. Its primary structures are the pterygopalatine ganglion and branches of the maxillary artery.
Pterygopalatine ganglion
Pterygomaxillary fissure

12. Sphenoid bone – posterior view
The pterygopalatine fossa is somewhat cone-shaped, located between the infratemporal fossa laterally and nasal cavity medially. It has six openings.
Sphenoid bone – posterior view
Infratemporal fossa
Nasal cavity

13. Six openings in to or out of the pterygopalatine fossa:
Infraorbital (V2) & artery
4. Inferior orbital fissure
Nasal nerves
Sphenopalatine artery
1. Foramen rotundum
Right side
Maxillary (V2)
6. Sphenopalatine foramen
Nasal Cavity
Infratemporal Fossa
2. Pterygoid canal
Greater petrosal nerve
5. Pterygomaxillary fissure
nerve of pterygoid canal (Vidian’s)
Maxillary artery
3. Greater palatine foramen
Greater & lesser palatine n.

14. Maxillary Artery entering pterygopalatine fossa
ECA
Maxillary artery arising from external carotid artery

15. The maxillary artery passes thru the pterygomaxillary fissure, giving off its 3 terminal branches. One is the sphenopalatine artery.
Maxillary a.
Spheno-
palatine artery
Sphenopalatine foramen
Pterygomaxillary fissure

16. 90% of nosebleeds are anterior bleeds, typically involving septal vessels.
Epistaxis means nosebleed
Ophthalmic artery
Internal carotid artery
Branches from ophthalmic a.
Sphenopalatine artery coming thru sphenopalatine foramen
Maxillary artery
10% are posterior nosebleeds.
Anastomosis between external & internal carotid systems
In the nasal cavity, the sphenopalatine artery ramifies over the posterior 2/3 of nasal cavity.

17. Another terminal branch of the maxillary artery is the infraorbital artery that passes thru the inferior orbital fissure.
Inferior orbital fissure
Infraorbital artery
Sphenopalatine foramen
Pterygomaxillary fissure

18. Inferior orbital fissure
Maxillary artery
Infraorbital artery

19. The 3rd terminal branch of the maxillary artery is the descending palatine artery.
Inferior orbital fissure
Infraorbital artery
Palatine foramen
Descending palatine artery

20. Descending palatine artery in palatine canal
The descending palatine artery exits the pterygopalatine fossa via the palatine canal and courses vertically downward to supply blood to the hard and soft palates.
Sphenopalatine a.
Maxillary artery
Descending palatine artery in palatine canal
Descending palatine artery on inferior surface of hard palate

21. The maxillary nerve enters the pterygopalatine fossa by passing thru foramen rotundum.

22. Lateral view of V2 Infraorbital nerve Foramen rotundum
Appears as continuation of V2.
Maxillary nerve

23. Opening of pterygoid canal
The nerve of pterygoid canal passes thru the pterygoid canal to enter the pterygopalatine fossa. The nerve ends at the pterygopalatine ganglion.
Opening of pterygoid canal
Greater petrosal n. passes into canal to become nerve of pterygoid canal (Vidian’s nerve)

24. Nerve of pterygoid canal from greater petrosal n.
The nerve of the pterygoid canal conveys parasympathetic preganglionic axons that synapse in the pterygopalatine ganglion.
Pterygopalatine ganglion V2
Nerve of pterygoid canal from greater petrosal n.

25. What is course of greater petrosal nerve?
Posterior entrance to pterygoid canal
Lesser petrosal nerve
Greater petrosal nerve
Crosses floor of middle cranial fossa
Geniculate ganglion
Facial n

26. Pterygopalatine ganglion Greater petrosal nerve VII
Para/pre
Para/post
Geniculate ganglion
Pterygopalatine ganglion
Greater petrosal nerve
VII
Superior salivatory nucleus
Nerve of pterygoid canal (Vidian’s nerve)
Nasal branches
(mucous glands)
Palatine nerves (mucous glands)
Greater palatine n.
Lesser palatine n.

27. Maxillary nerve V2

28. Lacrimal nerve
Somatosensory V2
Vidian’s nerve

29. Somatosensory from V1
Somatosensory from V2
Septum flipped up